Machinery for the packaging of rolls, especially toilet paper rolls, has to deal with the problem of misaligned rolls.
The rolls are normally fed along the conveyor lines lengthways, with their longitudinal axes aligned in the direction of feed, that is to say, in the same direction as the conveyors themselves extend.
This arrangement allows the rolls to be correctly fed into the packaging machines that wrap them, usually with plastic film, in packs of various sizes.
A problem common to prior art machinery of this kind is that of rolls becoming misaligned or upturned as they move along the conveyors. Misalignment or upturning may be due to any of various reasons.
Existing packaging machines are therefore equipped with suitable sensors designed to detect the outside shape of the roll and to interact with a control system which accordingly “perceives” whether the roll is correctly positioned, that is to say, with its longitudinal axis aligned in the direction of feed, or whether it is moving along in an incorrect position. When the roll is misaligned, however, this roll detection system does not detect the actual position of the roll and simply provides a generic incorrect position signal.
Once the sensors have detected an incorrectly positioned roll, they issue a stop signal which brings the packaging machine and the production line to a halt, resulting in considerable down time and significant losses.
To overcome this drawback, personnel is especially employed to remove or re-align incorrectly positioned rolls before these rolls are detected by the sensors. The workers are placed at the packaging machine or in the proximity of the roll position sensors and instructed to take corrective action before the incorrect position signal is issued so as to prevent the machine from stopping and avoid the consequent stoppages in production.
In other terms, manual labour is required to remove incorrectly positioned rolls from the production line or to realign them by hand on the conveyor that feeds them into the packaging machine.